package servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

@WebServlet
public class CheckCodeServlet extends HttpServlet {
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        int width =100;
        int height =50;
        BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();
        g.setColor(Color.PINK);
        g.fillRect(0,0,width,height);

        g.setColor(Color.BLUE);
        g.drawRect(0,0,width-1,height-1);

        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        Random ran = new Random();
        StringBuilder sb = new StringBuilder();
        for (int i=1;i<=4;i++) {
            int index = ran.nextInt(str.length());
            char ch = str.charAt(index);
            g.drawString(ch + "", width/5*i, height/2);
        }
        String checkCode_session = sb.toString();
        req.getSession().setAttribute("checkCode_session",checkCode_session);

        g.setColor(Color.green);
        for (int i=0;i<10;i++) {
            int x1 = ran.nextInt(width);
            int x2 = ran.nextInt(width);
            int y1 = ran.nextInt(height);
            int y2 = ran.nextInt(height);
            g.drawLine(x1,y1,x2,y2);
        }
        ImageIO.write(image,"jpg",resp.getOutputStream());


    }

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
